This invention relates to an improved apparatus for everting a tube or liner used in the lining of existing conduits and a method of everting the liner using the apparatus, and more particularly to an improved apparatus of smaller size than previously available which allows placing the apparatus in the same plane as the conduit to be lined which is not in the same plane as the stored liner, such as the bottom of a manhole when relining a sewer line or other underground pipeline.
A well-known process for rehabilitation of existing conduits, pipelines and passageways generally utilizing a flexible liner to be cured in place is the "Insituform.RTM." method. This method is described in U.S. Pat. No. 4,009,063 for METHOD OF LINING A PIPE and U.S. Pat. No. 4,064,211 for LINING OF PASSAGEWAYS, both to Eric Wood, the contents of which are incorporated herein by reference. In the later issued patent, a tube impregnated with resin is everted into the conduit utilizing a head of water. The head of water required to evert an 8-inch liner is approximately 23 feet. This requires a scaffolding structure of this height to support the tube and water. This procedure and an alternative apparatus is described in prior U.S. Pat. No. 5,154,936 for Apparatus for Everting of Tube which issued on Oct. 13, 1992 and U.S. Pat. No. 5,167,901, for Method for Everting a Tube which issued on Dec. 1, 1992, in which I was a co-inventor and which are assigned to Insituform Licenses BV. The contents of these prior patents are incorporated herein by reference.
Japanese application 01 204 726 shows an apparatus and corresponding method for everting a liner which can be placed in the invert of a manhole and aligned with an existing sewer line. Here, a sealing lip is used to contain the fluid for everting the liner in place of a sphincter valve. A single chamber for receiving everting fluid to force the everting hose out of the pressure vessel.
The apparatuses and methods for everting a tube or a liner for relining a conduit, such as a sewer pipe, gas line or water pipe described in U.S. Pat. Nos. 5,154,936 and 5,167,901 have been satisfactory. These available devices are capable of everting a tube impregnated with resin up to 18 inches in diameter. However, the design is heavy and this makes it difficult to handle in the field. Typically, such apparatuses are about six feet in height and about three feet in diameter. Since there is significant application and installations of diameters of 12 inches and smaller, it is evident that downsizing of such an apparatus and modifying the method to make it more efficient is highly desirable.
Accordingly, it is desirable to provide a compact apparatus and method for everting a tube or liner, especially an apparatus and a method of everting a tube which is more compact and efficient than presently available.